Source: Valent U.S.A.

Pre-emergence residual herbicides are topping researchers' recommendations for resistance management and overall weed strategy programs this spring. But with several pre-emergence residual herbicides on the market today providing a few days of control to several weeks of control, growers may be asking themselves: How long should a residual herbicide provide control of tough weeds?

University of Missouri Weed Scientist Kevin Bradley, Ph.D., said, "With residuals, the longer the control the better. I think two weeks of control is probably not enough out of any herbicide to really even justify spraying."

So exactly how much control should a grower expect from a residual herbicide? Bradley suggests at least a month of control is critical for both agronomic and economic benefit.

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